#ifndef CBIGINT_H
#define CBIGINT_H

/**
 * An integer number with unlimited number of digits. Low digit is at low address.
 *
 * @author Walter Roth
 */

//define the base type of the number here. Useable types are: char, short int
typedef char BaseType;
struct BaseStruct
{
    BaseType low;
    BaseType high;
};

union LongBaseType
{
    short int allSegments;
    BaseStruct Segment;
};

class CBigInt
{
public:
    /**
     * Default constructor. Creates a number with size zero digits.
     * Converts value to it's CbigInt representation.
     */
    CBigInt(int value = 0);

    /**
     * Copy constructor. Creates a deep copy.
     */
    CBigInt(const CBigInt & toCopy);

    /**
     * Destructor frees memory.
     */
    ~CBigInt();

    /**
     * Sets the new size, allocates memory and initializes with 0.
     * If newSize is smaller than old,* _Size is reduced as long as
     * digits to delete are zero. Returns final size.
     */
    int setSize(int newSize);

    /**
     * Returns the number of digits available (_Size)
     */
    int size() const;

    /**
     * Sets digit at position to value
     */
    void setDigit(int pos, BaseType value);

    /**
     * Operator +
     */
    CBigInt operator +(const CBigInt & n2);

    /**
     * Returns the number as a hexadecimal string
     */
    const char * toHexString()const;

    /**
     * Returns true, if LongBaseType is twice the size of BaseType
     */
    static bool isLongOk();

private:
    /**
     * Make a deep copy
     */
    void copy(const CBigInt & toCopy);

private:
    /**
     * The start of the digit-array. Points to LSB.
     */
    BaseType * _Digits;

    /**
     * The number of Digits allocated.
     */
    int _Size;

    /**
     * The string buffer for toXXString functions
     */
    static char * _StringBuffer;
}

#endif // CBIGINT_H